1. Field of the Invention
The present general inventive concept relates to a method and device to perform a handshaking process by using T.30 protocol between a sending-side fax machine and a receiving-side fax machine to transmit fax documents.
2. Description of the Related Art
Recently, voice over internet protocol (VoIP) is being used to replace public switched telephone network (PSTN). Thus, the PSTN network and the VoIP network may be usable in various section of a communication path between sending and receiving terminals. While the VoIP network has an advantage that its communication cost is low, there is a problem that data including fax documents experiences the loss of packets passing through the VoIP network or noise increases since it has been optimized for the transmission of a voice signal.
For example, T.30 protocol is used for handshaking procedures between sending and receiving fax machines is on the premise that the PSTN network is used. Thus, the T.30 protocol is vulnerable to the latency, jitter, packet-loss properties of the VoIP network. Moreover, since the VoIP network performs filtering and coding suitable for a voice signal band, messages according to the T.30 protocol may be distorted. As a result, there is a high probability that the communication between fax machines fails